Abstract
This paper analyzes the dynamics and the implementation of fractional-order algorithms in the position/force control of two robots holding an object. The experiments reveal that fractional algorithms lead to performances superior to classical integer-order controllers.

Abstract
This paper presents the implementation of fractional-order algorithms both for hybrid and cascade position/force control of robotic manipulators. The system performance and robustness is analyzed in the time and frequency domains. The effects joint backlash and flexibility are also investigated.

Abstract
This paper describes the implementation of a wireless data acquisition network for agricultural applications based on the Microchip PIC16C71, and the Intel 87C592 microcontrollers. The system uses a set of solar powered wireless data-acquisition stations (SPWAS) linked by radio frequency to a base station (BS). The base station has as main functions the control of the data-acquisition stations and the storage of the data collected by them. The network has been applied to collect outdoor and indoor climate data from a set of greenhouses located at Universidade de Tras-os-Montes e Alto Douro (UTAD), in the northwest of Portugal. Experimental tests are being done since mid June 1996, and the results obtained shows that the communications to the BS station were performed without errors and no loss of data.

Abstract
Greenhouse control computers are an essential part of modern greenhouse operation. Climate, irrigation and nutrient supply must be controlled, in an economical way, to produce the best crop conditions. Current research on CO2 enrichment and optimal growth strategies implies the use of powerful tools, either based on hardware or software. This paper describes the design and implementation of a distributed data acquisition and control system for computerised agricultural management systems that is being developed at Universidade of Tras-os-Montes and Alto Douro, Vila Real. Different communications platform concepts, such as Controller Area Network (CAN), Wireless Technologies, Ethernet and Internet tools supported by Transfer Control Protocol/Internet Protocol (TCP/IP) and e-mail tools supported by Simple Mail Transfer Protocol (SMTP) were used to achieve a network with a low-cost, flexible, and functional characteristics. The system management and maintenance tasks are divided into two types of performance levels. At a lower supervision level, a Local Controller placed in the greenhouses performs the monitoring/control and communications actions. The management decisions are performed at the higher level. The techniques and tools, which provide to the user a transparent, friendly and intuitive Graphical User Interface (GUI) will be presented.

Abstract
During the 2004, 2005 and 2006 growing seasons, physiological and anatomical leaf characteristics and productivity were studied in field-grown grapevines (Vitis vinifera L.) cv. 'Touriga Franca' under ambient (C, 365 +/- 10 ppm) or elevated carbon dioxide vertical bar CO2 vertical bar, (E, 500 +/- 16 ppm) under Open-top chambers (OTC-C and OTC-E, respectively). The elevated vertical bar CO2 vertical bar concentration increased net photosynthetic rate (A), intrinsic water use efficiency (A/g(s)), leaf thickness, Mg concentration, C/N, K/N and Mg/N ratios and decreased stomatal density and N concentration. Nevertheless, stomatal conductance (g(s)), transpiration rate (E), photochemical efficiency (F-v/F-m), leaf water potential, SPAD-values and Red/Far-red ratio transmitted by leaves were not significantly affected by vertical bar CO2 vertical bar. Meanwhile, there is no evidence for downward acclimation of photosynthesis and stomatal conductance. Yield, cluster weight and vigour showed an increase in elevated vertical bar CO2 vertical bar treatment but yield to pruning mass ratio was unaffected. Despite elevated vertical bar CO2 vertical bar stimulates grapevine photosynthesis and yield, more long-term studies, particularly at sub-optimal nutrient and water availability, are needed in order to reveal the grapevine responses to climate change in the Mediterranean area.

Abstract
In this paper it will be presented the aims and some of the results obtained in the project entitled "Development of Solutions for Instrumentation, Control and Management Applied to Agricultural and Fish Production Using Renewable Energies", sponsored by the Agriculture Ministry of Portugal. The experimental set-up is composed of three demonstration greenhouses and six aquaculture tanks for production of green beans, tomatoes and tilapias. Several actuators and sensors are connected to an acquisition and control network developed at the Engineering Department of the University of Tras-os-Montes and Alto Douro, Vila Real. The environmental factors controlled are: greenhouse inside air temperature and humidity, CO(2) concentration, and soil moisture. Dissolved O(2), pH, temperature and water nitrate concentration are also controlled in the fish tanks. Three types of heating systems are being used on the greenhouses and aquaculture tanks: a geothermal water source, a solar heat pump and a wood-gas combined heater. At the end of this project it is expected to achieve an efficient control in order to maximize the ratio production/costs. This implies the use of a supervisory module to perform high level management decisions. At this level, a decision support system helps the producer to establish the chemical treatment plans. This will also help to reduce environmental contamination as well production costs.